DF-2852 / verdict.json
{ "finding_id": "DF-2852", "status": "reproduced", "reproduced": 1, "impact": "none", "confidence": "certain", "verdict": "Line-accurate confirmation: the dev dispatch shim builds driver args structs on the kernel stack but leaves output fields uninitialized in three wrappers - dev_dmmap (kern_device.c:261-283) never presets a_result yet returns it on success; dev_dpsize (:448-467) same; dev_dclone (:310-326) fills only a_head so a_name/a_namelen/a_cred/a_mode are stack garbage. dev_dkqfilter (:471-473) documents the intended contract by explicitly presetting a_result=0. dev_dclone has zero callers (rg: prototype only; devfs_clone invokes handlers directly with initialized structs) and every in-tree d_mmap/d_psize sets a_result on success, so no current trigger - a future non-conforming d_mmap would hand an unpriv user an attacker-influenced physical page from leaked stack; a future dev_dclone caller would pass garbage cred pointers into privilege checks. Fix (preset a_result / bzero dclone args) compiled in the fix kernel.", "exploit_chain": "", "evidence": "sourcenote.txt: wrapper-by-wrapper analysis + dkqfilter contract", "kernel_refs": [ "sys/kern/kern_device.c:261", "sys/kern/kern_device.c:310", "sys/kern/kern_device.c:448", "sys/kern/kern_device.c:471" ], "poc_changes": "none", "attempts": 1, "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64", "runtime_sec": 20, "guest_dirty": 0, "build_cmd": "(source confirmation only)", "run_cmd": "(source confirmation only)", "code_hash": "23f7aa7264ff1e813a361845995afe420a9e249e3e35babdeb1a0d9d05c175c8", "notes": "dev_dclone is dead code (zero callers) - deletion is the alternative fix", "recommended_fix": "Preset a_result in dev_dmmap/dev_dpsize; bzero the args in dev_dclone (or delete it)", "fix_status": "compile_validated", "fix_baseline_reproduced": 0, "fix_patched_reproduced": 1, "fix_kernel_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #1: Mon Oct 26 01:57:23 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64 (h41 fix kernel, all 41 hardening fixes applied)", "fix_verdict": "Presets compiled and booted; identical dispatch behavior for conforming drivers." } |